JP5207499B2 - Phenol resin composite and method for producing the same - Google Patents

Description

  The present invention relates to a phenol resin composite material. More specifically, the present invention relates to a phenol resin composite material mainly composed of fine fibers, a phenol resin composition, and a fibrous base material.

  Conventionally, molded products in which cellulose fibers such as wood powder and paper pulp are added to thermosetting resins and the like have been manufactured. However, in recent years, fine fibers typified by cellulose nanofibers have attracted attention as plant pulp-derived materials. This cellulose nanofiber is obtained by mechanically opening wood pulp, removing components such as lignin and taking out only cellulose short fibers, and is composed of stretched chain crystals of cellulose. Therefore, it has the characteristics of very high strength and high elasticity and low thermal expansion coefficient. Thus, since cellulose nanofibers are derived from plant pulp and have excellent material properties, attempts have been made to add them to plastics as environmentally friendly reinforcing materials (see Patent Documents 1 to 3). .

  By the way, this cellulose nanofiber is normally supplied in a state containing a large amount of moisture (moisture is 50 to 90 wt% of the whole). This is because when cellulose nanofibers are in a dry state, strong adhesion occurs due to hydrogen bonding between the fibers, and it is difficult to redisperse the cellulose nanofibers in the dry state in water. Therefore, when cellulose nanofibers are added to plastics, it is necessary to remove moisture, and the following methods are used to remove this moisture.

As typical means, fine fiber such as cellulose nanofiber is made into a sheet by paper making in advance and impregnated with liquid resin such as phenol resin (hereinafter referred to as sheeting method), (see Patent Document 4), cellulose nano A method of mixing fine fibers such as fibers with a thermoplastic resin or a thermosetting resin such as a phenol resin and then kneading using a resin melt-kneading process apparatus typified by a twin-screw kneading extruder is used. (See Patent Document 5).
In general, as the thermosetting resin impregnated into the fibrous base material, an epoxy resin is used in addition to the phenol resin. However, it is extremely difficult or almost impossible to synthesize this epoxy resin by adding a material having a high water content such as cellulose nanofiber due to the water resistance problem of epichlordrin as a raw material monomer. .
Japanese Patent No. 3641690 JP 2006-312281 A JP 2006-31688 A JP 2004-292970 A JP 2005-42283 A

  When cellulose nanofibers are used, as described above, these nanofibers generally contain a large amount of moisture, and the removal of the moisture is extremely difficult. As a result of degradation of the resin due to hydrolysis, the strength of the molded product may decrease, or molding defects (appearance, weld, burr, molding accuracy decrease, etc.) may occur due to evaporation of residual moisture during molding. There was a case.

  Further, in the sheeting method, cellulose nanofibers are tightly bound and thus have poor drainage, making continuous paper making very difficult or impossible. Therefore, although it is possible to produce a sheet by suction filtration using a filter paper and a bifunnel funnel in the laboratory or by paper making by hand, these methods are not suitable for mass production. Furthermore, since the sheet obtained by the above method is very tightly packed, the impregnation property of the resin is poor and there is a problem that it is necessary to immerse for a long time at normal pressure after impregnation under reduced pressure.

  Further, a sheet made of fine fibers such as cellulose nanofibers formed on a filter paper is difficult to completely separate from the filter paper unless it is in a water-containing state, and cannot be completely separated from the filter paper when dried. It is necessary to remove the moisture from the sheet separated from the filter paper in the water-containing state. There has been a problem that the workability of the process is greatly hindered.

  Moreover, when using kneading apparatuses, such as the said twin-screw extruder, there exists a concern about the fall of the reinforcement effect by the cutting | disconnection of a cellulose nanofiber, and the hydrolysis of resin by residual water. Therefore, a separate dehydration step is required, but this step usually requires the installation of a vacuum pump or the like, and there is a problem that the manufacturing cost increases, such as a large facility.

  The present invention has been made in view of the above problems, and the object of the present invention is to easily remove moisture contained in fine fibers without reducing its strength, An object of the present invention is to provide a phenol resin composite material that can be manufactured at low cost, and a method for manufacturing the same.

  In order to achieve the above object, the phenol resin composite material according to the present invention is characterized in that a fibrous base material is impregnated with a liquid mixture composed of fine fibers and a phenol resin prepolymer and laminated.

  Moreover, the 2nd aspect of the phenol resin composite material which concerns on this invention is characterized by the said fine fiber being a cellulose nanofiber.

  Moreover, the 3rd aspect of the phenol resin composite material which concerns on this invention is characterized by the said liquid mixture containing the said cellulose nanofiber 0.1 to 5weight% as solid content.

  In the fourth aspect of the phenol resin composite material according to the present invention, the liquid mixture is a liquid obtained by adding a polymerization catalyst to a mixed liquid mainly composed of phenol and formalin to form a phenol resin prepolymer and adding a hydrophilic solvent. It is characterized by being obtained by mixing and dispersing the fine fibers after forming a resin.

  Further, in a fifth embodiment of the phenol resin composite material according to the present invention, the liquid mixture is obtained by adding a polymerization catalyst to a liquid mixture mainly composed of phenol and formalin to form a phenol resin prepolymer, and adding a hydrophilic solvent. It is characterized by being obtained by mixing and dispersing the fine fibers after forming a liquid resin.

  Further, the method for producing a phenol resin composite material according to the present invention is a method for producing a phenol resin composite material in which a fibrous base material is impregnated with a liquid mixture composed of fine fibers and a phenol resin prepolymer, and laminated molding is performed. In the step of obtaining the liquid mixture, after the first step of mixing and dispersing the fine fibers in a mixture mainly composed of phenol and formalin, a polymerization catalyst is added, and the mixture is heated and polymerized to obtain a phenol resin prepolymer. It consists of two processes.

  In addition, another method for producing a phenol resin composite according to the present invention is a method for producing a phenol resin composite in which a fibrous base material is impregnated with a liquid mixture composed of fine fibers and a phenol resin prepolymer and laminated. The step of obtaining the liquid mixture is a first step of adding a polymerization catalyst to a mixed solution mainly composed of phenol and formalin to obtain a phenol resin prepolymer, and adding a hydrophilic solvent to the phenol resin prepolymer to form a liquid It is characterized by comprising a third step of mixing and dispersing the fine fibers after the second step of making a resin.

According to the present invention, a phenol resin is a monomer, and a formalin usually uses a 37% aqueous solution of formaldehyde, so that fine fibers such as cellulose nanofiber containing a large amount of water can be directly mixed and obtained. Since the liquid mixture has a low viscosity, the fine fibers can be easily dispersed. Furthermore, since dehydration can be performed together with the condensed water generated in the polymerization process of the phenol resin, the water contained in the fine fibers can be removed at the same time using existing equipment.
Moreover, even when a hydrophilic solvent such as alcohol is added to a phenol resin prepolymer prepared in advance to form a liquid material, the water-containing component of the fine fiber is replaced with a hydrophilic solvent such as alcohol and then added to the liquid material. It is also possible to obtain a liquid mixture in which fine fibers are uniformly mixed and dispersed. These processes can also be performed by using existing equipment.
Moreover, since the fine fiber is uniformly disperse | distributed, the phenol resin composite material obtained using the liquid mixture obtained by the above processes has high intensity | strength.
Therefore, according to the present invention, it is possible to provide a phenol resin composite material that has high strength and can be manufactured at low cost.

Hereinafter, the present invention will be described in detail.
The fine fiber in this invention means the fiber refined | miniaturized to 1-10 nm in the thickness of a fiber, and what consists of a cellulose fiber especially in this invention is suitable as mentioned later. As raw fibers for the fine fibers, those derived from plants such as wood, agricultural waste, cloth and waste paper, those derived from microorganisms such as acetic acid bacteria, and those derived from animals such as sea squirts can be used. Considering the cost and availability, it is preferable to use a plant-derived material. From the viewpoint of protecting the global environment, it is also preferable to use cloths such as used paper such as newspapers and magazines, and used clothes made of plant fibers.
The fine fiber can be obtained by a known method. For example, the raw material fibers can be obtained by performing a predetermined treatment and then performing a treatment such as an ultra-high pressure homogenizer, a medium stirring mill treatment, and a vibration mill treatment.

As the fine fibers of the present invention, cellulose nanofibers derived from plant pulp are particularly suitable. As described above, this cellulose nanofiber was made by mechanically opening wood pulp, removing components such as lignin and taking out only short cellulose fibers, and was composed of stretched chain crystals of cellulose. Is. Therefore, it has the characteristics of very high strength and high elasticity and low thermal expansion coefficient.
Thus, since cellulose nanofibers are derived from plant pulp and have excellent material properties, they are particularly suitable as environmentally friendly reinforcing materials for plastics.

The phenols constituting the phenol resin prepolymer in the present invention are not particularly limited, and examples thereof include alkylphenols (cresol, xylenol, etc.), polyhydric phenols (resorcinol, etc.), phenylphenol, aminophenol and the like. Moreover, aldehydes are not specifically limited, Formaldehyde, paraformaldehyde, acetaldehyde, etc. are mentioned.
The phenol resin prepolymer may be either a resol type obtained by reacting phenols and aldehydes under an alkali catalyst or a novolak type obtained by reacting under an acid catalyst.
Moreover, as a fibrous base material in this invention, a cotton canvas, a paper sheet, glass fiber, a nonwoven fabric, etc. are mentioned, However It does not specifically limit.

The phenol resin composite material of the present invention can be produced, for example, as follows when cellulose nanofibers are used as fine fibers.
First, the molar ratio of phenol and formalin (37% formaldehyde aqueous solution) is P / F = 1 / 0.7 to 1 / 0.9 for novolak, and P / F = 1/1 to 1/3 for resol. Mix. Here, P / F means the molar ratio of phenol / formalin. As a polymerization catalyst, novolak is an acid catalyst such as oxalic acid, hydrochloric acid, sulfuric acid, toluenesulfonic acid, phosphoric acid and maleic acid. In the case of resole, sodium hydroxide, sodium carbonate, alkaline earth oxide / hydroxide, ammonia, hexa Alkali catalysts such as methylenetetramine and tertiary amine are used.

A predetermined amount of these monomers and cellulose nanofibers in a water-containing state are mixed, and mixed with a homogenizer at 8000 rpm for about 2 hours. As addition amount of a cellulose nanofiber, it is 0.1 to 5 weight% as a cellulose nanofiber solid content with respect to a phenol resin solid content. Preferably it is 0.5 to 3 weight%. When the addition amount is less than 0.5% by weight, a sufficient effect as a reinforcing material cannot be obtained. When the addition amount is more than 3% by weight, the liquid monomer is stirred during the polymerization reaction due to the thickening effect of cellulose nanofibers. Becomes difficult.
A polymerization catalyst is added to the mixture, and the mixture is heated and subjected to a polymerization reaction at normal pressure, and then subjected to reduced pressure, dehydration, and residual monomers to obtain a phenol resin prepolymer. The polymerization condition may be a generally known method, and is described in detail, for example, in “Phenol resin” (A. Knop, translated by Seto Shoji, Plastic Age, published in 1987).

  Further, it is particularly preferable to add a surfactant to this system because the uniform dispersibility of cellulose nanofibers can be improved. Although it does not specifically limit as said surfactant, In order to disperse | distribute a cellulose nanofiber (hydrophilic component) to a phenol resin (lipophilic component), a nonionic surfactant is preferable, and especially a lipophilic component and a hydrophilic component In view of this balance, alkylphenol surfactants are particularly preferred. Moreover, as addition amount, it is preferable to use in the range of 1 to 20 weight% with respect to cellulose nanofiber solid content (dry weight). When the content is less than 1% by weight, good dispersibility of the cellulose nanofibers cannot be obtained, and when the content is more than 20% by weight, the effect of improving the mechanical properties of the cellulose nanofibers in the phenol resin composite is inhibited.

  After the heat polymerization, it is preferable to keep at about 80 ° C. and efficiently remove unnecessary moisture of formalin, condensation reaction water of phenol and formaldehyde, and moisture contained in cellulose nanofibers under reduced pressure. As a moisture removal method, a general method such as removal under reduced pressure can be adopted, and it is not particularly limited.

  After removing water, a liquid mixture composed of cellulose nanofibers and a phenol resin can be obtained by adding an organic solvent such as methanol or acetone in an amount equal to or less than the calculated amount of phenol resin to obtain a varnish. The varnish (liquid mixture) is impregnated into a base material such as cotton canvas, paper sheet, glass fabric, non-woven fabric, etc., dried, cut into a predetermined size, and compression molded. A molded product can be obtained. In addition, a general method can be employ | adopted as a compression molding method.

In addition to the above, the phenol resin composite material can also be produced by the following method.
The phenols, the formaldehydes, and the polymerization catalyst are mixed to synthesize a novolac type phenol resin prepolymer or a resol type phenol resin prepolymer. The obtained phenol resin prepolymer is varnished by adding a hydrophilic solvent such as methanol. A predetermined amount of cellulose nanofibers in a hydrated state is added to the varnish.
In this case, cellulose nanofibers obtained by substituting the water contained therein with the same kind of hydrophilic solvent as the varnish can also be used. As the hydrophilic solvent used in this case, methanol, ethanol, isopropyl alcohol, and acetone are particularly preferable. Moreover, it is preferable to add a surfactant during the solvent replacement. The reason is because the cellulose nanofibers can be more uniformly dispersed as described above. Further, the usable surfactant and the amount used are also as described above.
After that, the liquid mixture obtained by stirring a mixed solution composed of cellulose nanofibers and a phenol resin prepolymer with a homogenizer is impregnated into a fibrous base material, dried, cut, and laminated to form a phenol resin composite of the present invention. The material can be a compression molded product.
In the following examples, the present invention will be described in more detail, but the present invention is not limited to the following examples.

To 282 g (3 mol) of phenol, 171 g (0.7 mol) of 37% formaldehyde aqueous solution and 75% of cellulose nanofiber (Serisch KY-100G, Daicel Chemical Industries, Ltd.) containing water were added in a solid content of 5 g (dry weight). 2 g of a nonionic surfactant (Emulgen 905, polyoxyethylene nonylphenyl ether, Kao Corporation) was added, and the mixture was stirred at 8000 rpm for 2 hours with a homogenizer (TK Homomixer, Primix Corporation).
This stirred product was treated with an ultrasonic homogenizer for 15 minutes, then transferred to a reaction vessel, and 3 g of oxalic acid dihydrate was added. The mixture was heated to reflux at 90 ° C. for 45 minutes in an oil bath while stirring.
Here, the reaction vessel was taken out of the oil bath, cooled to 80 ° C., and 2 g of oxalic acid dihydrate was added. The mixture is further heated under stirring, heated at a vacuum degree of 400 mmHg (53.3 kPa) until the internal temperature of the reaction vessel reaches 120 ° C., further heated to 160 ° C. and concentrated until no water droplets appear in the cooling tube. Thereafter, the reaction vessel was lowered to 80 ° C., 20 g of hexamethylenetetramine was added and stirred sufficiently, and 400 g of methanol was added to form a varnish to obtain a liquid mixture.

  The obtained liquid mixture was impregnated into cotton canvas (# 11, 0.8 mm thickness), dried and B-staged. The obtained impregnated cotton fabric had a smooth shape, and could be used for the subsequent cutting and compression molding as it was. This cotton canvas prepreg is cut, laminated 12 sheets, and compression molded using a stamping die at 160 ° C. and 10 MPa, and a molded product of 100 (width) × 150 (length) × 5 (thickness) mm. I got the material. This material was cured at 170 ° C. for 2 hours using a hot air circulating furnace to obtain a phenol resin composite material. A prototype of 100 (length) x 10 (width) x 4 (thickness) mm is produced from this composite by machining, and a bending test and a Charpy impact test are performed in accordance with JIS K7171 and JIS K7110, respectively. It was. The evaluation results are shown in Table 1.

To 282 g (3 mo1) of phenol, 292 g (1.2 mo1) of 37% formaldehyde aqueous solution and 75 g of cellulose nanofiber (Serisch KY-100G, Daicel Chemical Industries, Ltd.) containing water were added in a solid content of 5 g (dry weight). Further, 2 g of a nonionic surfactant (Emulgen 905, polyoxyethylene nonylphenyl ether, Kao Corporation) was added, and the mixture was stirred with a homogenizer (TK Homomixer, Primix Corporation) at 8000 rpm for 2 hours.
This stirred product was treated with an ultrasonic homogenizer for 15 minutes, and 10 g of 50% aqueous sodium hydroxide solution was added. The mixture was heated to reflux at 98 ° C. for 40 minutes in an oil bath while stirring.
Here, the reaction vessel was taken out from the oil bath, cooled to 60 ° C., neutralized by adding a 25% aqueous solution of acetic acid, and a vacuum distillation condenser was attached to the inside of the reaction vessel at a vacuum degree of 400 mmHg (53.3 kPa). The mixture was dehydrated at a temperature of 70 ° C. and stirred and refluxed for 2 hours. Thereafter, 400 g of methanol was added to form a varnish to obtain a liquid mixture.

  The obtained liquid mixture was impregnated into cotton canvas (# 11, 0.8 mm thickness), dried and B-staged. The obtained impregnated cotton fabric had a smooth shape, and could be used for the subsequent cutting and compression molding as it was. This cotton canvas prepreg is cut, laminated 12 sheets, and compression molded using a stamping die at 160 ° C. and 10 MPa, and a molded product of 100 (width) × 150 (length) × 5 (thickness) mm. I got the material. This material was cured at 170 ° C. for 2 hours using a hot air circulating furnace to obtain a phenol resin composite material. A prototype of 100 (length) x 10 (width) x 4 (thickness) mm is produced from this composite by machining, and a bending test and a Charpy impact test are performed in accordance with JIS K7171 and JIS K7110, respectively. It was. The evaluation results are shown in Table 1.

To the reaction vessel, 282 g (3 mol) of phenol and 292 g (1.2 mol) of 37% aqueous formaldehyde solution were added, and 10 g of 50% aqueous sodium hydroxide solution was added. The mixture was heated to reflux at 98 ° C. for 40 minutes in an oil bath while stirring.
Here, the reaction vessel is taken out from the oil bath, cooled to 60 ° C., neutralized by adding a 25% aqueous solution of acetic acid, and a vacuum distillation condenser is attached to the inside of the reaction vessel at a vacuum degree of 400 mmHg (53.3 kPa). The mixture was dehydrated at a temperature of 70 ° C. and stirred and refluxed for 2 hours. Thereafter, 400 g of methanol was added to make a varnish.
A cellulose nanofiber containing 75% by weight of water (Serisch KY-100G, Daicel Chemical Industries, Ltd.) 25 g of water substituted with methanol by a centrifuge was added to the varnish, and a nonionic surfactant (Emulgen 905, 10 g of polyoxyethylene nonylphenyl ether, Kao Co., Ltd. was added, and the mixture was stirred for 2 hours at 8000 rpm with a homogenizer (TK homomixer, Primix Co., Ltd.) to obtain a liquid mixture.

  The obtained liquid mixture was impregnated into cotton canvas (# 11, 0.8 mm thickness), dried and B-staged. The obtained impregnated cotton fabric had a smooth shape, and could be used for the subsequent cutting and compression molding as it was. This cotton canvas prepreg is cut, laminated 12 sheets, and compression molded using a stamping die at 160 ° C. and 10 MPa, and a molded product of 100 (width) × 150 (length) × 5 (thickness) mm. I got the material. This material was cured at 170 ° C. for 2 hours using a hot air circulating furnace to obtain a phenol resin composite material. A prototype of 100 (length) x 10 (width) x 4 (thickness) mm is produced from this composite by machining, and a bending test and a Charpy impact test are performed in accordance with JIS K7171 and JIS K7110, respectively. It was. The evaluation results are shown in Table 1.

To the reaction vessel, 500 g (5.3 mol) of phenol and 500 g (6.2 mol) of 37% aqueous formaldehyde were added, and 20 g of 25% ammonia solution was further added, and the mixture was stirred in an oil bath at 98 ° C. for 40 minutes. Heated to reflux.
Here, the separable flask was taken out from the oil bath, cooled to 60 ° C., neutralized by adding an acetic acid 25% aqueous solution, and dehydrated at a vacuum skin of 400 mmHg (53.3 kPa) at an internal temperature of 70 ° C. The mixture was stirred and refluxed for 2 hours. Thereafter, 5 g of an emulsifier (Homogenol L-95, Kao Corporation) and 200 g of purified water were added to obtain a varnish of an aqueous dispersion resol resin.
25 g of cellulose nanofiber containing 75% water (Serisch KY-100G, Daicel Chemical Industries, Ltd.) is added to the varnish, and a nonionic surfactant (Emulgen 905, polyoxyethylene nonylphenyl ether, Kao Corporation) ) 10 g was added, and the mixture was stirred at 8000 rpm for 2 hours with a homogenizer (TK homomixer, Primix Co., Ltd.) to obtain a varnish (liquid mixture).

  The obtained liquid mixture was impregnated into cotton canvas (# 11, 0.8 mm thickness), dried and B-staged. The obtained impregnated cotton fabric had a smooth shape, and could be used for the subsequent cutting and compression molding as it was. This cotton canvas prepreg is cut, laminated 12 sheets, and compression molded using a stamping die at 160 ° C. and 10 MPa, and a molded product of 100 (width) × 150 (length) × 5 (thickness) mm. I got the material. This material was cured at 170 ° C. for 2 hours using a hot air circulating furnace to obtain a phenol resin composite material. A prototype of 100 (length) x 10 (width) x 4 (thickness) mm is produced from this composite by machining, and a bending test and a Charpy impact test are performed in accordance with JIS K7171 and JIS K7110, respectively. It was. The evaluation results are shown in Table 1.

(Comparative Example 1)
A pulp for kraft paper (fiber diameter: 20 to 80 μm) that is not a fine fiber was used, and a phenol resin composite material composition was prepared as follows.
To 282 g (3 mo1) phenol, 292 g (1.2 mo1) of 37% formaldehyde aqueous solution and 5 g of pulp containing 75% water (for kraft paper) are added in solid content, and nonionic surfactant (Emulgen 905, polyoxyethylene) 2 g of nonylphenyl ether, Kao Co., Ltd. was added, and the mixture was stirred at 8000 rpm for 2 hours with a homogenizer (TK homomixer, Primix Co., Ltd.).
This stirred product was treated with an ultrasonic homogenizer for 15 minutes, then transferred to a 1000 mL separable flask, and a 50% aqueous solution of sodium hydroxide was added. The resulting mixture was heated to reflux at 98 ° C. for 40 minutes in an oil bath while stirring.
Here, the separable flask was taken out from the oil bath, cooled to 60 ° C., neutralized by adding 90 g of a 25% aqueous solution of acetic acid, attached with a condenser for distillation under reduced pressure, and the internal temperature at a vacuum degree of 400 mmHg (53.3 kPa). It dehydrated at 70 degreeC and stirred and refluxed for 2 hours. Thereafter, 400 g of methanol was added to obtain a varnish (liquid mixture).

The obtained liquid mixture was impregnated into cotton canvas (# 11, 0.8 mm thickness), dried and B-staged.
The obtained impregnated cotton fabric had a smooth shape, and could be used for the subsequent cutting and compression molding as it was. This cotton canvas prepreg is cut, laminated 12 sheets, and compression molded using a stamping die at 160 ° C. and 10 MPa, and a molded product of 100 (width) × 150 (length) × 5 (thickness) mm. I got the material. This material was cured at 170 ° C. for 2 hours using a hot air circulating furnace to obtain a phenol resin composite material. A prototype of 100 (length) x 10 (width) x 4 (thickness) mm is produced from this composite by machining, and a bending test and a Charpy impact test are performed in accordance with JIS K7171 and JIS K7110, respectively. It was. The evaluation results are shown in Table 1.

(Comparative Example 2)
Using a rayon fiber (fiber diameter, about 15 μm) which is not a fine fiber, a phenol resin composite material composition was prepared as follows.
To 282 g (3 mo1) of phenol, 292 g (1.2 mo1) of 37% formaldehyde aqueous solution and 5 g of rayon fiber (for paper blending) containing 75% of water are added in a solid content, and further a nonionic surfactant (Emulgen 905, polyoxy) 2 g of ethylene nonylphenyl ether, Kao Co., Ltd. was added, and the mixture was stirred with a homogenizer (TK homomixer, Primix Co., Ltd.) at 8000 rpm for 2 hours.
This stirred product was treated with an ultrasonic homogenizer for 15 minutes, then transferred to a 1000 mL separable flask, and a 50% aqueous solution of sodium hydroxide was added. The mixture was heated to reflux at 98 ° C. for 40 minutes in an oil bath while stirring.
Here, the separable flask was taken out from the oil bath, cooled to 60 ° C., neutralized by adding 90 g of a 25% aqueous solution of acetic acid, attached with a condenser for distillation under reduced pressure, and the internal temperature at a vacuum degree of 400 mmHg (53.3 kPa). It dehydrated at 70 degreeC and stirred and refluxed for 2 hours. Thereafter, 400 g of methanol was added to form a varnish to obtain a liquid mixture.

  The obtained liquid mixture was impregnated into cotton canvas (# 11, 0.8 mm thickness), dried and B-staged. The obtained impregnated cotton fabric had a smooth shape, and could be used for the subsequent cutting and compression molding as it was. This cotton canvas prepreg is cut, laminated 12 sheets, and compression molded using a stamping die at 160 ° C. and 10 MPa, and a molded product of 100 (width) × 150 (length) × 5 (thickness) mm. I got the material. This material was cured at 170 ° C. for 2 hours using a hot air circulating furnace to obtain a phenol resin composite material. A prototype of 100 (length) x 10 (width) x 4 (thickness) mm is produced from this composite by machining, and a bending test and a Charpy impact test are performed in accordance with JIS K7171 and JIS K7110, respectively. It was. The evaluation results are shown in Table 1.

(Comparative Example 3)
Cellulose nanofibers were dispersed in water to prepare a slurry having a solid content of 0.2%, and this was filtered under reduced pressure using a bifunnel funnel and a suction bottle with filter paper on it, to obtain a cellulose nanofiber sheet having a thickness of 0.15 mm. . The cellulose nanofiber sheet was peeled off from the filter paper one by one in a water-containing state, dried while being sandwiched between cotton linters and pressurized (0.05 MPa) with a compression molding machine. The cotton linter was replaced every day, and it took 4 days for the water content of the sheet to be 1%.

To the reaction vessel, 292 g (1.2 mol) of 37% aqueous formaldehyde solution was added to 282 g (3 mol) of phenol, and 10 g of 50% aqueous solution of sodium hydroxide was added. The mixture was heated to reflux at 98 ° C. for 40 minutes in an oil bath while stirring. Here, the reaction vessel was removed from the oil bath, cooled to 60 ° C., neutralized by adding a 25% aqueous solution of acetic acid, attached with a condenser for distillation under reduced pressure, and an internal temperature of 70 ° C. at a vacuum degree of 400 mmHg (53.3 kPa). And then stirred and refluxed for 2 hours.
Using this phenol resin and methanol, a phenol resin varnish having a solid content concentration of 15% was prepared, and impregnated with cellulose nanofibers after drying. The impregnation operation was held under reduced pressure of 600 mmHg for 12 hours, and further maintained at normal pressure for 96 hours, and then the sheet was taken out and air dried.
60 sheets of this sheet were laminated and compression molded using a stamping die at 160 ° C. and 10 MPa to obtain a molded product material of 100 (width) × 150 (length) × 5 (thickness) mm. It was. This material was cured at 170 ° C. for 2 hours using a hot air circulating furnace to obtain a phenol resin composite material. A prototype of 100 (length) x 10 (width) x 4 (thickness) mm is produced from this composite by machining, and a bending test and a Charpy impact test are performed in accordance with JIS K7171 and JIS K7110, respectively. It was. The evaluation results are shown in Table 1.

From Table 1, in Examples 1 to 4, compared with Comparative Examples 1 and 2 that are not fine fibers, the time required for moisture removal is the same, but bending strength, bending elasticity, and Charpy impact strength are excellent. You can see that In addition, compared with the case of the comparative example by the conventional manufacturing method, each physical strength is slightly inferior, but the time required for water removal is extremely short, delamination does not occur, and productivity is excellent. I understand.
Thus, according to the present invention, it is possible to provide a phenol resin composite material composition with high productivity while increasing the physical strength as a composite material.

Claims (7)

A liquid base material comprising a fine fiber and a phenol resin prepolymer is impregnated into a fibrous base material, and is formed by lamination. The fine fiber is a cellulose nanofiber, and the liquid mixture contains the cellulose nanofiber. A phenol resin composite containing 0.1 to 5% by weight as a solid content . 2. The phenol resin according to claim 1 , wherein the liquid mixture is obtained as a phenol resin prepolymer by mixing and dispersing the fine fibers in a mixture of phenols and aldehydes, adding a polymerization catalyst, and heating and polymerizing the mixture. Composite material. The liquid mixture, phenol and a mixture a polymerization catalyst was added phenolic resin prepolymer aldehydes, after a liquid resin obtained by adding a hydrophilic solvent, to claim 1, obtained said fine fibers were mixed and dispersed The phenolic resin composite as described. The phenol resin composite material according to claim 2 or 3, wherein the mixed solution of phenols and aldehydes is a mixed solution of phenol and formalin. A method for producing a phenol resin composite material in which a fibrous base material is impregnated with a liquid mixture composed of fine fibers and a phenol resin prepolymer, and laminate molding is performed.
The fine fibers are cellulose nanofibers, and the liquid mixture contains 0.1 to 5% by weight of the cellulose nanofibers as a solid content,
The step of obtaining the liquid mixture is a step of adding a polymerization catalyst after the first step of mixing and dispersing the fine fibers in a mixed solution of phenols and aldehydes, and heating and polymerizing to a phenol resin prepolymer. The manufacturing method of the phenol resin composite material characterized by consisting of a process. A method for producing a phenol resin composite material in which a fibrous base material is impregnated with a liquid mixture composed of fine fibers and a phenol resin prepolymer, and laminate molding is performed.
The fine fibers are cellulose nanofibers, and the liquid mixture contains 0.1 to 5% by weight of the cellulose nanofibers as a solid content,
The step of obtaining the liquid mixture includes a first step of adding a polymerization catalyst to a mixed solution of phenols and aldehydes to obtain a phenol resin prepolymer, and adding a hydrophilic solvent to the phenol resin prepolymer to obtain a liquid resin. A method for producing a phenol resin composite material comprising a third step of mixing and dispersing the fine fibers after the step of 2. The method for producing a phenol resin composite according to claim 5 or 6, wherein the mixed solution of phenols and aldehydes is a mixed solution of phenol and formalin.